Lubricating oil compositions



United States Patent 3,254,027 LUBRICATING OIL COMPGSHTIONS Howard J. Matson, Harvey, and John W. Nelson, Lansing, Ill., assignors to Sinclair Research, Inc., Wilmington, DeL, a corporation of Delaware N0 Drawing. Filed Jan. 28, 1963, Ser. No. 254,456 1 Claim. (Cl. 252-466) This application is a continuation-in-part of now abandoned application Serial No. 185,186 filed April 5, 1962. This invention relates to lubricating oil compositions having improved extreme pressure properties. More particularly, the present invention is directed to lubricating oils having a markedly increased Timken safe load value.

Among the several extreme pressure tests that lubrieating oil blends are generally required to meet is the regular Timken break-down test. Many gear oil consumers, for instance, specify a high T imken load, usually a 50-pound minimum safe load Now, although there are many excellent extreme pressure agents that provide highly satisfactory results with regard to other extreme pressure tests such as the Shell-4 Ball Wear, Falex and SAE tests, it is not uncommon in many cases to find that they fail to meet the Timken safe load specifi-- cations. For this reason, particular interest is currently shown in materials that will increase T imken safe load values.

It has now been found that the addition to lubricating oils of small effective amounts of each of a sulfurized fatty oil and certain phosphorus compounds will provide the oil with a minimum Timken safe load of 50-, and in most cases a minimum Timken safe load of 60.

The oil-soluble phosphorus compounds of the present invention are those selected from the following groups, designated 1, II, III, IV and V:

I. A tris(2-halohydrocarbon)phosphorus having the general formula:

s X IiE (OCH2( JHR)3 wherein R is hydrogen or an alkyl radical, including cycloalkyl, of up to 13, preferably 4 to 8, carbon atoms on the average, X is a halogen atom of 17 to 53 atomic number, ie, chlorine, bromine or iodine, and y is selected from 0 and l. The prefered halogen is chlorine. The alkyl chains can be straight, cyclic or branched, preferably straight chain or at least no branching in the 1- or 2- positions, and can be substituted with non-interfering groups. When branched, the alkyl chains often have the side chain at the 3 or higher position.

The tris(2-halohydrocarbon)thiophosphate can be prepared, for example, by reacting in molar ratio of about 3:1, a 1,2-epoxy-alkane of up to carbon atoms with PSX wherein X is a halogen atom and the tris- (2-halohydrocarbon)phosphite by similarly reacting the epoxy-alkane with PX Alternatively, the compounds can be prepared, for instance, by reacting a Z-halo-alkanol- 1 with PSX or PX in a molar ratio of 3:1 using an amine such as pyridine, triethylamine, etc. as a hydrogen halide acceptor. The preferred method of preparing the thiophosphate compounds is by sulfiding with flowers of sulfur, the phosphite derivative.

II. A bis[di(alkylphenyl phospho) Jbenzene having the general formula:

s s wherein R is an alkyl group of 1 to 18 carbon atoms,

preferably 4 to 12 carbon atoms, and y is selected from O to 1. It can be prepared, for instance, by the concompound 3,254,027 Patented May 31, 1966 ice densation reaction of an alkyl-substituted phenol, PCl or PSCl and hydroquinone to provide an oil-soluble product. The alkylated phenols employed are the monohydric phenols, having at least one alkyl group, for instance, in an orthoor para-position, i.e., non-meta position. Alternative alkyl phenols are those in which the alkyl group contains 1 to 18 carbon atoms, preferably 4 to 12 carbon atoms, for example amyl phenol, octyl phenol, nonyl phenol, p-tert-butyl phenol, p-tert-octyl phenol, a mixture of phenols and the like. The alkylated phenol is one which gives an oil-soluble product in the condensation reaction.

In the reaction, the alkylated phenol to PCl or PSCl to hydroquinone molecular ratio is about 412:1, although slightly less or greater amounts of a given component may be used. Any method may be employed to produce the condensation product, but the preferred method comprises the following:

A two-step procedure wherein (1) A stoichiometric amount of the alkyl-substituted phenol dissolved in a suitable solvent is slowly added to the PO1 or PSCl in the presence of a hydrogen chloride acceptor such as pyridine. In this first step (RO) PCI or is formed wherein R represents the alkyl-substituted phenol radical of the phenol.

(2) In the second step the proper amount of hydroquinone dissolved in a suitable solvent is then slowly added and allowed to react with the remaining chlorine atom to couple the two (RO) PCl or (RO)2|1|C1 molecules and form the condensation product.

III. Alkyl phenyl phosphorus compound having the general formula:

R o R wherein R, R and R" are alkyl radicals of up to 18 carbon atoms, preferably 4 to 12 carbon atoms with one of alkyl radicals being dissimilar to the other two alkyl radicals and y is selected from 0 to 1. The compounds can be prepared, for instance, by reacting an alkyl-substituted phenol with PCI;, or PSCl in the presence of a hydrogen halide acceptor as described with reference to compound II above. In the case of forming the preferred phosphorous compound, an amount of alkylated phenol is first added sufiicient to remove two of the chlorine atoms from the PCl or PSCl and then the second alkylated phenol is added in a proper amount to react with the remaining chlorine atom. Suitable alkyl-substituted phenols are mentioned in the disclosure to compound II above.

IV. An 0,0-dialkyl-l-alkyl-dithiophosphate having the structural formula:

wherein R is an alkyl group of 1 to 12, preferably 4 to 8 carbon atoms, and R is an alkyl group of 4 to 12 carbon atoms, preferably 6 to 8 carbon atoms, and Z is selected from hydrogen and a hydroxy group. This compound can be prepared, for instance, by treating P S with the desired alcohol in molar ratio of 1:4:2. The resulting 3 0,0-dialkyldithiophosphoric' acid is then treated with the desired alcohol or in the case of the OH group containing phosphorus compound with an excess of alkylene oxide until essentially neutral, washed, dried and topped under reduced pressure.

V. An oil-soluble phosphorus compound having the general formula:

wherein R and R are alkyl radical of up to 13, preferably 2 to 8, carbon atoms on the average and they may be the same or different straight or branched chain; Y is selected from sulphur and oxygen; Q is selected from hydrogen, R and YR; 11:0 to 1 and P=phosphorus. The preparation of these compounds is well known to the art. Usually phosphoroustrichloride, phosphorus oxychloride, phosphorous triochloride, alkyl phosphodichloride, hydrogen phosphodichloride alkyl phosphorous thiodichloride or hydrogen phosphorous thiodichloride is reacted with the desired alkanol or alkyl mercaptan of 2 to 13 carbon atoms. Thus, depending on the reactants selected the resulting compound can be a phosphate, phosphite, phosphonate, phosphonite or the thio derivatives thereof.

The sulfurized fatty oil which forms the second component of our additive combination may be a fatty oil having 12 to 22 carbons in the fatty or acid radical sulfurized as, for example, at about 350 F. for 6 hours with sulfur flowers to provide about 9 to 14% sulfur in the ultimate product. The oil which is sulfurized preferably contains unsaturated ester components. It is generally added to the lubricating oil in minoramounts, [for instance about 2 to 10, preferably about 3 to 5%, by weight which amounts ordinarily raise the Timken safe load to 30 or 40 pounds maximum. The phosphorus components of the present invention when added in minor amounts of, for instance about 0.1 to 2%, preferably about 0.25 to 1% by weight appear to potentiate the activity of the sulfurized oil so that the resulting lubricating oil composition generally meets the Timken safe load of about 50, preferably 60, minimum. The result is surprising in that, for example, 1% by weight of the phosphorus compounds alone raises the Timken break-down load to 18 pounds yet one-half of this percentage of the phosphorus compounds, i.e., 0.5% by weight, when added to a lubricating oil containing say, 4% sulfurized sperm oil, brings the Timken safe load to about 50 or 60 pounds, whereas 4.5% of sulfurized sperm oil alone fails to raise the Timken breakdown load beyond 40 pounds. Although more than 1% by weight of the phosphorus compounds of the present invention can be employed, ordinarily about 0.25 to 0.75% by weight is all that is necessary to bring the Timken load to at least about 50 or 60 pounds.

Thus, the proportions of sulfurized oil to phosphorus compound employed in the novel additive combination can fall in the range of say, about 2:1 to 16:1, but is more commonly about 7 to 9:1. The weight percent employed of the combination itself is generally about 2 to 10% preferably about 2.25 to 6% by weight.

The lubricating oil base stock used in the present invention is of lubricating viscosity and can be, for instance, a solvent extracted or solvent refined mineral oil obtained in accordance with conventional methods of solvent refining lubricating oils. Generally, lubricating oils have viscosities from about 20 to 250 SUS at 210 F. The base oil is present in major amounts and may be derived from paraffinic, naphthenic, asphaltic or mixed base petroleum crudes and if desired, a blend of solvent-treated Mid-Continent neutrals and Mid-Continent bright stocks may be employed. A particularly suitable base oil used in the preparation of the composition may be described as a lubricating mineral oil fraction having a viscosity index of about 100.

The following examples are included to illustrate the preparation of the phosphorus compounds of the present invention.

Example I.Tris(2-chl0r01octyl) phosp/zite mixture allowed to stir for 1.25 hours before heat was applied. After 2.25 hours the ether was refluxing. Twenty grams of ether were then added to reduce the reflux temperature to 120 C. It was heated and stirred for 1.5 hours. A drying tube was attached to the end of the reflux condenser and the clear colorless solution allowed to stand overnight. The next day it was topped to 153 C. at 6 mm. A 78% yield was obtained.

Example II.1,4-bis(di0ctyl phenyl phosphite)benzene A 5-liter, fluted, 4-necked flask, equipped with a powerstat controlled heating mantle, thermometer, motor driven paddle stirrer and nitrogen inlet tube was used. The flask was flushed with nitrogen and a blanket of nitrogen continued during the addition of octyl phenol. The flask was then charged with 514 g. (6.5 moles) pyridine followed by 274 g. (2 moles) of PCl in 500 g. toluene. The PCl was weighed directly into the toluene to minimize contact with air and hydrolysis with the moisture in the air. After mixing the flasks contents thoroughly, 824 g. (4 moles) paratertiary octyl phenol dissolved in 1000 g. toluene were added dropwise over 2.5 hours. During this addition 400 g. toluene were added to reduce the viscosity of the agitating mass, and the temperature rose from room temperature to 53 C. Some cooling was employed by blowing a stream of air on the outside of the flask. After the addition of the phenol a Dean-Stark trap, and water cooled reflux condenser capped with a drying tube were attached to the flask. The nitrogen blanket was discontinued and entrance neck of the flask plugged. Agitation was continued and heat was applied to the mantle. The flask contents had a white precipitate, but the mixture was fluid enough for good mixing. After 1.3 hours and at a temperature of 102 C. the contents of the flask had turned to a tan color. One and a quarter hours later at 116 C. the toluene was refluxing and some of it was removed periodically through the trap. Some pyridine was lost in this process. After about 3.5 hours and the temperature still 116 C. the run was shut down for overnight. The reaction mass now had an orange color. The next morning g. (1 mole) pyridine was added to insure the presence of enough pyridine to take up the hydrogen chloride formed in the next step. Then g. (1 mole) of hydroquinone dissolved in 800 g. of ether was added while stirring the mass. The heat was turned on and after 15 minutes and at 55 C. ether was. removed periodically to raise the temperature of the refluxing mixture. After 3.25 hours the removal of ether was discontinued since the pot temperature was 113 C. The removed ether contained no HCl when tested with a few drops of NaOH and phenophthalein indicator. The reaction was allowed to continue for 4.25 hours at 112 to 113 C.

The mass was then transferred to a beaker and allowed to stand overnight. The next day it was filtered through a Biichner funnel and the filter cake washed with ether and toluene and discarded. The filtrate weighed 2837 g. and 1987 g. of this were washed with a dilute solution of NaHCO using ether and methanol to break the emulsion formed. This was followed by 3 washes with 1:2 parts of water and methanol. The crude undried product was then topped to C. at 10 mm. The product weighed 632 g. representing a 91.5% yield. It was a cloudy off- Example III.Di (para tertiary octylphenyl) para tertiary butylphenyl phosphite The equipment used was a 5-liter, fluted, round bottom, 4-necked flask, equipped with a motor driven stirrer, heating mantle controlled with a powerstat, thermometer and a nitrogen inlet tube. The flask was flushed with nitrogen and a nitrogen blanket was maintained throughout the first step of the reaction. The flask was charged with 277 g. (3.5 moles) pyridine and 137 g. (1 mole) PCl and 500 g. toluene. The PCl was weighed directly into the toluene to minimize hydrolysis with the moisture in the air. Then While agitating vigorously, 412 g. (2 moles) para tertiary octyl-phenol dissolved in 500 g. toluene were added over 40 minutes, during which time heat was applied to the mantle, 300 g. of toluene were added and the temperature rose from 28 to 58 C. The nitrogen inlet was closed and a water cooled condenser capped with a drying tube, was attached to the flask. Heating was continued and refluxing of the toluene, at 113 C., maintained for over 2.5 hours, before shutting down for the night. The next day, 300 g. (2 moles) para tertiary butylphenol dissolved in 800 g. toluene were added over 15 minutes. The mass was then heated at 105 to 114 C. for 7 hours. It was filtered hot 3 times because washing the filter cake caused a precipitate to form in the filtrate. It was then allowed to evaporate down over a weekend. The volume was thus reduced to one-half the original. It was washed twice with water and methanol and dried over Drierite. It was filtered and treated with Attapulgus clay at room temperature for 2 hours and again filtered. Finally it was topped to 205 C. at 18 mm.

Example I V.--0,0' diamyl-I -ctzm0I-Z-dithiophosphate In standard laboratory equipment one mole of P were treated with 4.2 moles of a mixture of 70% primary and 30% secondary amyl alcohols. While stirring the temperature was raised to 140 to 170 F. over 4 hours.

and then held at 170 F. for 8 hours. The product analyzed 11.35% P and 21.7% S. To 0.95 moles (261 g.) of this 0,0-diamyl dithiophosphoric acid 1.85 moles (250 g.) of octenyl oxide (95% oxirane) while stirring and cooling over 16.5 hours. After the first 7.5 hours the acid number was 12.1, after 10.5 hours, 7 and 16.5, 6. The mixture was then washed with N21 CO solution until essentially neutral, extracted with ether and dried over Drierite. It was then topped to 75 C. at 5 mm. pressure. Some cracking occurred under these conditions. Thereafter the product was treated with Attapulgus fines and filtered through Su-percel. The clear, slightly yellow product analyzed acid number 2.9, percent S 14.0, percent P 7 .45.

Example V To the regular Timken load break-down test were subjected (1) a base oil designated Base Oil 1 consisting essentially of 30% solvent refined Mid-Continent neutral having a viscosity of 46 SUS at 210 F. and 200 SUS at 100 F. and 70% of a solvent refined Mid-Continent bright stock having a viscosity of 120 to 125 SUS at 210 F. and a viscosity index of 85 to 90;

(2) the base oil of (1) above containing 4.0% sulfurized sperm oil and the composition designated Base Oil 2;

(3) the base oil of (1) containing 4.5% sulfurizied sperm oil;

(4) the base oil of (1) containing 1% by weight of the additives of Examples I through IV, and the thiophosphate derivatives of the additives of Examples I to III;

(5) 0.5% of the additives of Examples I to IV and the thiophosphate derivatives of the additives of Examples I to III in the base oil composition of (2).

Tests on other additives of the present invention are also included. The results of the tests are summarized in Table I below. 1

TABLE I Oil Blend Reg- Timken ular p.s.i

Base Oil No. 1 6# 5, 646 Bzse Oil No. 2 (4% sulfurized sperm oil) 35# 18, 329 Base oil No. 1 plus 4.5% suliurized sperm oil 40# 21, 472 Base oil No. 1 plus 1% tris (2-chloro-1-octyl) phosphite (803-037 5) 21# 16, 949 Base oil No 2 plus 0.5% tris (2-el1loro1 octyl) phosphite 17, 521 Base oil N 0. plus 0.5% tr hl ctyl) thiophosphate (8036084) 28,254 Base oil No. 1 plus 1% 1,4-bis ny phite) benzene (803-6065) 18# 14, 490 Base oil N o. 2 plus 0.5% 1,4-bis (dioctylphenyl phospJite) benzene 60# 28, 843 Base oil No. 1 plus 1% 1.4l)is (dioetylphenyl thiophosphate) benzene (803-6097) 9t 7, 986 Base oil No. 2 plus 0.5% 1,4-bis (dioctylphenyl thiophosphate) benzene 50# 25, 024 Base oil No. 1 plus 1% di(oetylpheny1) butylphenyl phosphite (803-6091) 9# 8, 339 Base oil No. 2 plus 0.5% di(0otylphenyl) butylphenyl phosphite 50# 33, 890 Base oil No. 1 plus 1% di(octylphenyl butylphenyl thiophosphate 50# 20, 311 Base oil No. 1 plus 1% 0,0-diam phosphate (803-6021) 18# 17, 108 Base oil No. 2 plus 0.5% 0,0'-diarny1-1-butanol-2-dithiophosphate 6014 36, 433 Base oil No. 2 plus 0.5% 0,0-diamyl-1-butanol-2-dithiophosphate Base oil No. 1 plus 1% 0,0-diamyl-1-decyl-dithio phosphate (803-6317) 1- 12# 10, 106 Base oil N0. 2 plus 0.5% 0,0-diamyl-1-deeyl-dithiophosphate 50# 25, 205 Base oil No. 1 plus 0.5% tris(2-chloroethyl) phosphite. 15# Base oil No. 2 plus 0.5% tris(2-ohloroethyl)ph0sphite Base oil No. 2 plus 0.25% tris(2-chloroethyl)phosphite..

Example VI 0.5% by weight of the phosphorus compounds identified in Table II below were individually added to a commercial gear oil composition A, comprising 93.3% of Base Oil No. 1 of the Example V and percent Additive package X 6.7 Acryloid 0.10 Polysilicone fluid 3 0.005 Maskodor 0.003

Additive package X consists of 30% phosphosnlfurized mineral oil bright stock having a viscosity at 210 F. of 1-15 to SUS and containing 2. 5% maximum sulfur and 3.0 to 3.4% phosphorous, 67.5% sulfurized sperm oil containing 11.0% minimum sulfur and having a viscosity of 230 to 290 SUS at 210 F.. 2.2% lanric acid and 0.3% trioxane.

A eopolymer of methncryllc acid esters as a viscosity index improver.

3 A defoaming agent.

4 A deodorant.

These compositions thus prepared were subjected to the Timken load test and the results are shown in Table II below.

No attempt was made to determine actual safe loads that were in excess of 80 pounds, to avoid damage to the Timken tester.

7 Example VlI 0.25% of tris (2 -chloroethyl) phosphite was added to the Base Gear Oil of Example VI containing the same additives except that 6.75% of additive package X of the example was employed and the blend subjected to the 5 Timken safe load test. For comparative purposes a blend of 0.5% of tris (2-chloroethyl) phosphite in the same oil without additive package X and a blend of 7.0% of the additive Package X in the base oil without the tris(2- chloroethyl) phosphite were also tested. The results are 1O 1 See footnote 1 at end of Table II.

The data of Example VII and Tables I and II demonstrate the advantageous Timken load values obtained by use of the sulfurized fatty oil-phosphorus compound com bination of the present invention.

We claim:

A lubricating oil composition having an improved Timken breakdown load value consisting essentially of a major amount of a mineral oil of lubricating viscosity and small effective amounts of each of a sulfurized fatty oil having 12 to 22 carbon atoms in the fatty acid radical and an oil-soluble phosphorus compound having the general formula:

S y wherein R is an alkyl radical of 1 to 18 carbon atoms and y is selected from O tol, said small amounts being sufficient to improve the Timken breakdown load value of said mineral oil.

References Cited by the Examiner UNITED STATES PATENTS 2,157,452 5/1939 Humphreys 25246.6 2,220,851 11/ 1940 Schreiber 252-46.6 2,231,301 2/ 1941 Smith 25246.6 2,242,260 5/1941 Prutton 25246.6 2,722,517 11/ 1955 Smith 25249.9 2,991,250 7/1961 Socolofsky 25246.7

DANIEL E. WYMAN, Primary Examiner. 

